Air conditioning apparatus



' Dec. 1,1936." T -B R, PETERS r 2,062,605 Y AIR CONDITIONING APPARATUS: l l

FiledApfil 1, 1935 5 sheets-Shea '1 T. B. R. PETERS i AIR CONDITIONING APPARATUS Filed April 1, 1933' :s sheets-'sheet' T. B. R. PETERSv 2,062,605 AIR CONDITIONING APPARATUS l 6 Dec. l, 1936.

3. Sheets-Sheet l3 Filved Aprilv l Patented Dec. `1, 1936 t f l y Y l UNITED STATES. PATENT ofi-FICE Thomas B. R. Peters, Chicago, Ill., assig'nor of one-sixthto Alexander D. Bruce, and one-sixth to Edward A. Russell," Chicago, and one-sixth to Walter W. Wilson, Oak Park, Ill.`,

A Application April 1, i933, serial No. 663,968

'-3 claims. (c1. 15s-42.4)

This invention relates to new and useful imthe heatexchanger so as to maintain a predeterprovements in air conditioning apparatus, parmined relative humidity in this air stream. ticularly adapted for the heating and humidica- The principal object of this invention is to prof tion of air, and includes means and methods of vide an improved air conditioning method and controlling the temperature and percentage of. apparatus such as briey described hereinabove 5 entrained moisture of the air, means and methand disclosedmore in detail in the specifications ods of controlling the combustion of the fuel, which follow. v Y A c and means and methods of controlling the flow of Another Object iS t0 Provide en improved the products of combustion and of the airtobe means for controlling and positively forcing the L0 heated through the heat exchanger. ow of products of combustion and air through 10 The invention relates particularly to the art the heat exchanger. l

of air conditioning as applied to automatically Another Objeet iS t0 Provide means for ther--` controlled domestic plants as used in homes, mostatically' Controlling fthe OW Of fuel tothe small buildings, railway passenger coaches, or burners. similar enclosures. The apparatus is of the type Another Object iS toy providev improved means 16 in which heat is derived from the combustion of for Cutting Off the iiow- Of fuel to the burners `in i huid fuel such as oil or gas, the products of comoase the fen ceases to function properly. bustion being passed directly through a heat ex- Another object is to provide improved means changer in which the greater portion of thc heat for cutting off the flow, of fuel to all the burners units are transferred to a stream of the air to be in CaSe all of the names become extinguished.

heated which is. forced through the heat ex- Another Object iS t0 DI'OVide improved signal- 20 changer and then conductedto the space whereling apparatus fOI indicating thet'the pilot burnin the heated air is to be utilized. A motor-driven er has been extinguished.` fan is used for drawing the products of combusother Ob'jeOtSndndi/entages Of this invention tion successively ythrough the heat exchange will be more apparent from the following de- 25 units and then discharging these products of tailed description of certain approved forms of combustion into and through an outlet ue after aPDaTatuS oOnStueteli and Operating accordi!! a maximum proportion of the heat units have to the pfinople of this invention; t been transferred to the air Awhich is also forced In the aooompenyingdre-Wingsi through the heat exchanger by a power-driven Fig- 1 iS a Perspective View. partially broken o blower. Means is provided for automatically away, Showing the Principal elements of the air l' cohcrciung the. operation of thc combustion. conditioning apparatus. i f l burners in accordance with temperature changes Fig- 2 is avholizohtal section through the heut in the place to the heated, and means are proexohangel Showing One `blink Of the heat exvided for auiomaticahy contrcuing'thc fan which Change units in Ploni i g 35 exhausts the products of combustion so that this *Fg- 3 is a Partial Vertical Section. token Suhr fan wili not be startedin operation until after- Stantiany 0n the une 3 -3 0f Fig- 2- l the burners have been ignited, and will be 'con- Fig- 4 is a detail Vertical section through one of tinued in operation for a brief interval after the the heat, exchange units 'the View hoih taken 4o burners have been extinguished so as to withsubstantially on the une H of Fig' 3' 40 draw the remaining products of combustion from Fig' 5 1s a? getan Vertical section taken substan' the heat exchanger. A pilot burner which nortlai oggleahgrlgsi incldin a' o l M e- 'malisf bums contlfmously 1s posmoned m 9: maticshowing of the principal' elements of the auxiliary ue leading into and from the main air conditionin a Matus 4 combustion chamber, and safety means is prog pp 45 vided for cutting off the ilowof fuel to all burnma??ejgsnmhtprgsst nglhe die: ers in the event that all of the names are exelements of the apparatus and am, embodies the tinguished at any one time'. Additional electricair conduit for directing the air to b hr d 5U ally operated safety mechanism is provided-for through the heat exchanger. Within the ci hg 50 cutting oi the ow of fuel to the ,burners in case A is mounted the assembly B oi eat exch ge the fan OeaSeS 'to operate to' draw the Products units through which the product il' combu Jn of combustion `through the heat exchanger. --are passed, the burner assembly idicated .n- Means is also provided for automatically introerally at'C being connected direct w*h th'e- Let ducing water into theair stream drawn through end of this heat exchange asa .b y am' 1e l let end of assembly B so as to draw the hot gases through the heat exchanger. The fan .or blower indicated at' E forces air through thecasing A in contact with the heating element B and discharges this heated air through the outlet conduit F. A mechanism indicated generally at G isA positioned within the casing A so as to add moisture to the air stream owing through casing A and maintain the desired percentageof humidity in this air'stream. Automatic control connections are provided for these several elements as will be hereinafter described.

The heat exchange assembly. B comprises a plurality of-similar heat exchange units I each comprising a .casting formed with a central tubular portion 2 of elongated cross section enclosing the gas passage 3, a series of spaced apart ns 4 being ,cast integrally about the central tubular portion 2. In the preferred form here shown the fins 4 are so shaped as to give the unit an outer rectangular cross' section making it convenient to arrange the units in closely spaced parallel rows or banks and providing `a maximum' of heattransferring surface to be engaged by the air stream which passes in intimate contact with the exposed outer surfaces of the fins 4 and tubular conduit 2. Preferably these heat exchange units are cast integrally of aluminum, although other metalsmay be used. Those 'units positioned at the inlet end of the series, into which the highly heated products of combustion are directly discharged from the burners, are preferably provided with inner sleeves or linings 5 of Monelmetalor other suitable heat-resisting metal. The remainingunits of the series may be made 'entirely of aluminum. While the form of heat exchange unit just described is preferred, it will be apparent, as

the description proceeds, that other forms of heat exchange units having adequate heat transfer surfaces could be substituted without departing from the general principles; of this invention.

While any suitable number of these heat exchange units may be used, in the example here` shown six of these units are arranged in two superposed horizontal banks of three units each. Each of the units I is provided at each end with a header Shaving an inner chamber 1 (see Fig. 5)

communicating through opening 6 with the pas# sage 3 in the casting I. The header 6 may be an iron casting and is preferably provided in its opposite. sides and inl its top and bottom with threaded openings to be engaged'by suitable conduit fittings whereby the units are connected in series. The threaded openings not usedl for this purpose may be closed by threaded plugs 9 in the usual manner.

As shown in Figs. 1 and 2, the headers III'at the 4 ad inlet end of the assembly B serve as a portion of' the housing for the burner assembly C, and the headers 6 at the outlet end of the firstv units are connected by horizontal nipples or fittings I I with the headers 6 at the inlet ends'of the second row of units. The headers 6 at the outlet ends of this second row are connected by -ttings I2 with .the

headers at the inlet end of the third row and so on throughout the series. While each horizontal bank -of units may if preferred remain separate from the next adjacent bank, it is preferable to connect the superposed headers by vertical sleeves I3 (see Fig. 3) so that the superposed units throughout the series are connected in parallel.

thus forming virtually a single series of increased capacity. Preferably drains I4 are prQYQil in the bottom of certain of the headers 6 to permit the withdrawal of the condensate which forms lfrom the products of combustion as they lose their heat to the air owing in contact with the units I. Ordinarily no such drains will be necessary for the firstv row ofunits into which the burners directly discharge the products of combustion, but

such drains should be provided at the outlet ends of the units in Yeach succeeding row of. the series. A pipe or conduit I5 leads from the header 6 at the outlet end of the last unit of the series to the fan D which is driven by the motor I6, this fan positively drawing the products of combustion through the heat exchange assembly B and discharging these cooled gases into the main iiue I1.

The' main casingA is mountedon a plurality 4of suitable supports I6, and the heat exchange assembly B is housed within the lower portion of this casing. A screened air inlet or lter I9 is provided at a'suitable location in the upper portion of the housing', and the blower E driven by motor 20 draws in air through inlet I9. and forces this air downwardly through passage 2| and thence horizontally backward through passage 22 around and between the finned conduits ofthe heat exchanger B so that a maximum proportion of the heat is transferredto this air -stream from the products of combustion flowing through-these f `adjacent the outlet end of the-series, which are at the lowest comparative temperature, and then successively engages with the more highly heated units, contacting last with the unit into which the products of combustion are directly discharged from the burners C.1- In other words, the air stream fiowsin a direction substantially opposed to the direction of iiow'oi.' the heating gases. This permits the temperature of the products of combustion to be lowered almost -to the temperature of the inlet air before these combustion products are discharged into the outlet flue I1.

The housing for the burner assembly C .com-

prises the'connected headers I0 already referred to and an auxiliary iiue comprising a lower inlet section 23`and an upper outlet section 24.

In the present example a pair of similar burners 25 and 25' are adapted to project the 'combustion materials into the respective headersri,

I the combustion takes-place within these headers.

and within the adjacent passages 3 o f, the heat y exchange units at the inlet .end of the series. A normally constantly burning pilot flame 26 is maintained `within the inlet section 23 of the auxiliary flue-directly` beneath the main combustion chamber. In the present example,'the burner assembly is adapted to utilize gaseous fuel, although byv making suitable alterations in the type of burner used, oil or other Aliquid fuel might be substituted. The supply pipe 21 leads from a suitable source of fluid supply to the electrically operated automatic cut-off valve 26 from which pipe 29 provided with the usual air` valve 30 leads throughl suitable branches to the' two burners 25 and 25'. `The fuel for pilot flame 26 is supplied through pipe 3| leading from the pipe 21 at the inlet side of valve 26. An electrically operated valve 32 is positioned in pipe line 3|, this valve' being open during the normal operation of the -apparatus but closing `automatieally to shut off the flow of gas to the pilot burner when the safety -circuit inwhich valve 32 is connected is broken. If the pilot flame becomes extinguished the valve 32 will automatically close. In order to permit the pilot to be re-lighted, a bypass pipe 33 is provided extending around the valve 32 and provided with a normallyy closed valve 34 which is preferably a push-button valve or. other valve of an automatically closing typev which must be manually held open while the pilot flame is being lighted. When the system is in normal operation, the by-.pass 33 will remain closed and the pilot will receive its fuel through the pipe line 3| and valve 32. The combustion air for the burners flows in through flue 23 and n valve 30. When the main burners are extindraft through auxiliary fiue 24 serves as' an outlet for the combustion gases from pilot flame 26, and also' for the main burner flames when these burners are first ignited. However, during the normal operation of the system all of the combustion products will be drawn through the heat exchange 'assembly B by the suction provided by fan D, the gases being 'discharged through the main iiue I1. l

The means C+ is provided for adding additional moisture to the air stream which is drawninto and forced through casing A, when this ,becomes necessary in order to maintain the desired relative humidity in this air stream. 'Ihis mechanism comprises a sprayer positioned within casing A, preferably in the intermediate airpassage 2|, the sprayer being supplied with water through pipe 36 provided with the automatic electrically operated cut-olf valve 31. This water :i5 maybe pre-heated by rst -passing the water through a coil 36' positioned about thel exhaust. pipe I5. The excess water from sprayer 35, not absorbed by the air stream, is caught ina pan 38 provided with drain 33 (see Fig. 6). A suitable humidostat 40 is positioned within casing A'in the path of the air stream so as to automatically control the water supply valve 31. In the preferred form here shown this humidostat inclosed by a wick or boot 4| which extends 'into a receptacle 42 maintaining a constant supply of water. As-here shown, a bleeder pipe 43 extends from the main water supply pipe 36 and drips into receptacle 42 which is provided with a drain pipe 33' to remove excesswater. Alternatively the pan or receptacle 42 might `be supplied with water from thev water collected in pan 33 from the sprayer 35.

The safety circuits and automatic control cori-4 nections will now be described, referring more particularly to Fig. 6. 'I'he mainpower lines 44 and 45 are energized from a suitable source of electric supply through the main power switch 46. The motor 20 for operating the main air blower E which forces the air stream through the heating apparatus is energized through the following circuit: from positive .main 44 through wire 41, switch 43, motor 23, wire 43, temperature-controlled stack switch 56, and wire 5| toI the negative main 45. With switch 43 closed the blower E will operate provided the airin discharge stack -.F has been raised to a suitable temperature so as toclose the automatic switch 53. This switch -'prevents the circulation of'cold air when the system is first started up', and permits the blower E to continue to -operate after `the burners are shut off to extract the remaining heat units from the conducting surfaces of the heat-exchanger B. l

75 A low voltage control circuit for the humidostat guished and fan D is not operating, the natural' comprises a wet bulb thermostat having its bulb g 3 43 extends from the transformer 52 (energized from the power lines through wires, 52a and 52h) through wire 53; to upper contact 54 positionedl in the thermostat stem. A lower contact `55 in this thermostat stem is connectedthrough wire 56 with the relay magnet'51 from which wire 53 extends baok to transformer 50. The mercury column 53 ofthe thermostat is normally in engagement with the lower contact 55, and when the desired wet-bulb temperature is reached (which 10 corresponds to the desired relative humidity of the air) this mercury column will `engage the upper contact 54 thus completing the control cir'- -cuit and energizing the magnet coil 51 so as to lift the armature 60 out of engagement with the fixed 15 i contact 6|. .The energizing circuit for water supply valve 31 extends from positive main 44 through wire`62,'valve 31, wire 63, xed contact 6|, armature 63, and ywire 64 to the negative main. When the magnet 51 is deenergized, the arma- 2'0 ture 60 will fall or be` drawn into engagement with fixed contact 6| thus completing the valve actuating circuit and opening the valve 31, so that the sprayer 35 will operate. It will be apparent that the lower lthe relative humidity 0f Y the air stream may be, that is the less4 the per-V centage of entrained moisture in the air, theJ greater will be the rate of vaporization'fromthe wick 4|, thus absorbing heat from the thermometer and lowering the mercury column 53. As the 30 relative humidity of the air is increased, the rate of vaporization will be' decreased and the mercury column will rise. When the desired relative hunudity is attained,the mercury column will en- Ease the upper contact 54 thus. completing the4 35v control circuit` and causing magnet 51,'to be -eril ergized thus lifting armature 60 andbreaking the?. valve actuating circuit so that valve 31 will automatically close and shut oif the supply of water to the sprayer 35.- 1 Conversely., as the relative hu- 40 midity of the air is'lowe'red, the control circuit i will be broken by mercury column 53 fallingout of engagement with contact 54 thus deenergifzing magnet 51 and closing the valve actuating 'circuit to open valve 31 kand again start the sprayer 35 45 Y in operation. f

A safety flame-controlled circuit of known type comprises a wire or rod 55 which is insulated from the metallic portions of theburner assembly` but extends vertically downward through aux`v 50 A iliary flue 24 so as to normally extend through the main burner flames and project into the pilot 'flame 26. Three similar relay magnet coils 466.

51'and 63-are connected in series by wires 63 'and 1li, and the otherterminal of ,magnet 6,3 is con'- 55 nected through wire 1| with the flame-engaging rod 65. The other terminalof magnet 66 is conn ected through wire 12 with one terminal of' transformer 13 which is energized from the mains 44 and 45 through wires 14 and 15. A wire 16 in 60. which a suitable vacuum tube `11 is connected ex-. tends from the other terminal of transformer 13 to the movable armature 13 which is .normally heldin engagement with fixed contact 13 bythe energized relay coil 30. Wire 3| `extends from 66 fixed contacty 13 and is grounded at 32 on the metallic structure of the burner assembly. As long as any one fof the burner flames contacts` with the this safety circuitwill lie-come`I p`eted as followszFrom transformer 13 through 70- wire 13, tube 11, armature 13, xed contact 13, wire 3|, the metallic structure of the burner as -l sembly and the flame onda-mes to rod 35, wire 1|,

thus be normally energized, but will be deenergized when all of the flames have 'been extin-` mally maintains this control circuit complete.`

.Relay coll 66 normally holds the movable armature 83 in engagement with fixed .contact 84.

Relay coil 61 normally holdsthe armature 85 in engagement with the fixed contact 86. Relay coil 68 normally holds the armature 81 out of engagement with ythe fixed contact 88, but this amature 81 willbe moved into engagement with fixed contact 88 when coil 68is deenergized.

The cut-off valve 32 in the supply pipe 3| leading to the pilot burner is normally held open by current flowing over the following circuit: From positive main 44 through wire 88, valve 32, wire 80, lfixed contact 86, armature 85, and wire 8| back to the negativelmain. When the pilot ame is extinguished, relay 61 will be deenergized thus permitting armature 85 to move -out of engagement with fixed contact 86 thus breaking this valve actuating circuit and permitting valve 32 to automatically close and cut oif the supply of fuel to thepilot burner.

Transformer 82 is energized from the mainsv 44 and 45 through wires 83 and 84. The thermostat indicated at 85 is positioned at any desired location within the building so as to be responsive to temperature changes at that location and control the main fuel supply valve 28. The control circuit extends from transformer 92 through wire 86, amature 83, fixed contact 84, wire 91, valve 28, wire 88, thermostat 85, andv wire 88 yback to transformer 92. When this circuit is completed valve 28 will be opened, and when the circuit is broken valve 28 will automatically close. thermostat 85 is adapted to break this circuit when the desired temperature has been attained in the building, thus causing valve 28 to close and 4 temporarily shut down the main burners.v Also,

in case the pilot flame 26 is extinguished, the relay 66 will be deenergized thus breaking the circuit between armature 83 and fixed contact 84 and causing the main valve 28 to close.

The pivotally mounted mercury-tube switch is provided'in one end portion with a pair of spaced apart fixed contacts which will be bridged by the mercury globule |0I when the switch is tilted to the position shown in Fig. 6. The valve operating mechanism forvalve 28 is provided with suitable mecanism such as indicated Aat' |02 for tilting the mercury tube switch |00 so as to close this switch after valve 28 has been completely opened, and conversely to tilt switch |00 in the opposite direction so as to open this switch after the valve 28 has been completely closed. The motor I6 which operates the fan D is ener- .gized through the following circuit: From positive main 44 through wire |03, motor I6, wire |04, mercury tube switch |00, and wire back to the negative main 45. The delay action mechf anism |02 permits the motor I6 and i'an D to ,remain inoperative until the valve 28 has been opened and the mainburner flame is ignited from pilot 26, but immediately thereafter the fan D is started in operation to draw the prodtion 24'of the auxiliary due. normally energized through' the following cir- The changer, this continued action being provided by the delayed opening of the switch |08, and the natural coast of the fan mechanism.'

When the pilot flame is extinguished and relay;-

coil 68 is deenerglzed, a lshunt circuit is c'ompleted from wire |04 through wire |06, fixed contact 88, movable armature 81,- wire |01, signal light |08, and wire |08 to wire |05 of the motor circuit. The illuminated signal light |08 will ind ica'te that the pilotflame has been extinguished and should be relighted.

A normally closed temperature-operated circuit breaker I|0 is positioned in the outletsec- Relay coil 801s cuit: From' positive main 44 through wire circuit breaker |I0, wire ||2, relay coil 80, and wire I3 to the negative main.` In case the fan I6 should-cease to function while the main burners are in operation, the products of combustion will no longer be' drawn through the heat ex. changer B but will be drawn upwardly by the natural draft through fiue\ 24.' temperature in flue 24 will cause the circuit breaker ||0 to open thus deenergizing the relay 80 and permitting the armature 18 to move out 'of contact with fixed contact 18 thus breaking 'I'his excessive f the main control circuit and deenergizing the several relays 66, 61 `and 68 and causing both gas valves to be closed and the signal |08 to be illuminated.

It will be notedfthat when the main flame controlled circuit is broken, an energizing circuit for fan' I6 is completed through the signal light |08 and switch 81, 88. This permits the fan I6 to continue to operateto withdraw gases from the heat exchanger.` The motor I6. may be stopped by opening the main switch 46. This shunt circuit also permits the fan motor I6 to be energized and fan D to be operated before the system is started up, to'discharge any unfiashed gases or products of combustion from the apparatus before the burners are ignited.

Whenthe apparatus is to be started in opera;-

' tion, main switch 46 will first be closed, thus starting the fan D to withdraw any` unilashed gases from the system.L Switch ,48 may also be closed, but'the main blower E will not start until the air in stack F has been raised to a suitablel temperature so as to close the'automatic, switch 50. The manually operated valve 84 in by-pass 33 is now opened so as to furnish gas to the pilot light which is ignited iny any suitable manner. With this pilot light burning,` the main control circuit will be established so as to energize the relays 66, 61 and 68. From this time on the system will function in the normal manner under control of the room thermostat 85, and the fan D` will only operate at such times as the main burners are functioning. 'I'he main air blower E will remain continuously in operation 's'o long as the air in discharge conduit F has been raised to a suitable temperature, unless the motor "cirautomatically to add Vmoisture to the air stream `whenever necessary to maintain the-desired relative humidity.

In ythe preferred form of the apparatus herein disclosed,- a portion of the discharge air conduit F is adapted to be' used as a drying apparatus, particularly for drying laundry, 'although it might be used for other drying purposes. A door ||4 is 'provided in one wall lof-the stack or ,conduit F to provide access to .that portion v ing fuel to .bothbumers l trclled electrically actuated valve for the oi the conduit which iorms the dryi ober. A normally open valve or damper li is provided in stack F directly shove the drying cham-I discharge conduit il@ leads ery conduit being closed velve Sil. velve'il is cl euxiliary outlet HE.

I claim:

l. In heating apparatus, a combustion -chsmber, a uid-fuel burner operatively associated with the scoii'ibusticn chber, a normally constently burning pilot-burner, means for supply- .con-

s, thermostatic burner and a' normally open electrlcll Aeon-f tri-oiled valve for cutting oil.' the Supply of luci to the pilot-burner, a main' `disree due, s.

main discharge passage connecting the commis# l tion chamber and the main flue, e :noter-driven fan for drawing theproducts of combustion through the main passage for heat-transfer purposes and discharging `these gases through the main ue, an auxiliary flueleading directly from the combustionchamber': operative4 to vent the combustion chamber of'gases whenthe fan is not' in operation, and means` comprising a control circuit including the valves and a. tempere-l ture-responsive switching mechanism operatively associated with the lauxiliary ilue to cause said valves to"close if a ture is exceeded in the auxiliary ue.

2. In heating' apparatus, al. combustion chamber, a viuid-iuel burner operatively associated with the combustion chamber,-means. for sup plying fuel to the burnerv comprising sin elec.-l

o trically actuatedvalve a mein discharge flue, a

cheeses directly irom the combustion to vent the comhustien chamber of eases when predetermined tempera.

tion chamber and mein discherse nue, e motordriven fen ior drawing, products ot combus-y tion hroueh the discharge sage 'for heatthrough the ein dus, lary iiue leading mem hai-ss passage ceimeeiins thev comme;

chamber operative the ian is not in ration, and mesns comprlsi ing s. control circuitincluding the yalve and a n temperetureresponsive switching @mechanism operatively ociated with the auxiliary due to cause said valve to clcse oi iuel to the burner ii a predete tempersiture is exceeded in the auxiliary ihre.'`

3. in heating eppsretus,v a combustion chber, c. duid-fuel `burner otively lated with the combustion chambenmeansor sup-'v `ply'i fuel to the burner including en electrlcelly 'ectu'a` valve, a mein discharge flue.

s mein discharge passage connecting the corn-y bustion chamber and main discharge iue, .a motor-driven ian for drawing the products of 'combustion through the transfer pur and discharging the eases through the mein ue,

an' auxiliary ,ilue leading .directly from the combustion chamber operative to vent the gases when ation, an' electrical actuatingy circuit for the Ian motona switch in said circuit positioned to be .closed when'said valveis opened. and, vice versa, so that the fan will the burner is in operatic a.v temperature-,re-

` sponsivelswitch operatively associated with the auxiliary flue, and electricallyoperated mechanism controlled by said last-mentioned switch for closing the valve whereby. if vthe fan falls tooperate, Ythe passage of heated gases through said auxiliary flue will shut down the burner.

the fan is not in oper-y to cut oi the simply.

normally operate when 

